Thermal modelling of PMMA microfluidic separation chips

Understanding the thermal performance of electrokinetically driven microfluidic chips is important since Joule heating could raise the temperature significantly and affect the separation efficiency. In this paper, we present the thermal modeling of polymethylmethacrylate (PMMA) polymer separation chips using computational methods with a whole-chip approach. Both a simple cross and a multichannel separation chip were used in the study. The numerical study was carried out using the multiphysics CFD package CFD-Ace+. The heat generation was essentially uniform and the subsequent temperature increase was uniform along the channel(s) except for regions near the liquid ports. For the simple cross chip, the Joule heating effect was negligible for the studied conditions. For the multichannel separation chip, the heat generation was much higher and the maximum temperature could reach over 80°C at an electric field of 68kV/m one minute after the separation starts. For moderate electric field (∼45kV/m), the heating effect was also significant and it is suggested that active heat dissipation measures be used for polymer chips to alleviate excessive temperature rise.